1. Field of the Invention
The present invention relates to a structure for fixing a bulb to a lamp and, more particularly, to a lamp bulb fixing structure having a fixture for fixing a socket portion of the bulb to a lamp body, a reflector or the like.
2. Description of the Related Art
Vehicular lamps for motor vehicles and the like adopt a fixing structure for detachably fixing a bulb using a bulb mounting hole formed in a back side portion of the reflector or the lamp body, in order to meet requirements for bulb replacement. FIG. 12 shows an example of such bulb fixing structure. A circular ring-shaped mount part 103 is integrally connected to or formed together with a bulb mounting hole portion 102 of a reflector 101 disposed in a lamp body. A fixture 104 is fixed to the mount part 103 with screws 105. The fixture 104 has the shape of a circular shallow dish with an insert hole 107 formed on its bottom portion 106 for inserting a bulb to be fixed. An inner periphery defining the insert hole 107 has a plurality of engagement cut outs 108 that are formed in different positions along the periphery.
A bulb (not shown) to be fixed to the bulb mounting hole portion 102 is integrated with a bulb socket that has a boss portion. The boss portion has projected engaging pieces that are formed in a plurality of positions distributed in the circumferential direction. The bulb socket of the bulb can be fixed to the fixture 104 of the above-described fixing structure by fitting the boss into the insert hole 107 of the fixture 104 so that the projected engaging pieces of the boss substantially engage or align with the engagement cutouts 108 of the fixture 104, and then turning the bulb a small angle about its axis so that the engaging pieces are clamped between the fixture 104 and the end face of the bulb mounting hole portion 102. The bulb can be detached simply by conducting the procedure in the reverse order.
However, since the fixture is screwed to the reflector in the conventional bulb fixing structure, the screws required for the fixture add to the number of component parts of the fixing structure. Such an increase in the number of component parts is not desirable for cost reductions. Furthermore, the operation of tightening the screws adds to the manhours for assembly of the lamp.